My favourite of the run so far, this one. I’ll get that said right at the start. The set-up this time is Bill moving into a student house with her friends, with them basically finding themselves unable to afford the bunch of cupboards-masquerading-as-flats that they’re shown. As with each episode this run, it takes its time setting things up (again, no dashing out of the gate here), and we get a flavour of the guest characters. But still no sign of anywhere for them all to live. Enter a mysterious man who looks like an older version of that Poirot fella off the telly, who offers them an enormous house, with just one or two conditions in the contract. As you might expect, small print should be read. And as it turns out, David Suchet’s terrific, understated performance is just one of the highlights of this episode, one that sees Bill and the Doctor more apart than together. In fact, there’s something gleefully old fashioned and patient about it, an episode that could easily be set in the past as much as in the present day. The sonic screwdriver is put away again, and it’s down to a bit of brainpower to work out just what’s going on. Without spoiling it, I really think this one delivered in the last third, too. One or two of the episodes this run have done the build up very well, and had to rush to wrap things up. Not here. To talk more would inevitably start to give things away, and I’m absolutely not going to do that. Instead, I’ll leave it for now by saying that Knock Knock slowly creeps up on you, takes very relatable fears and really turns the screw on them. If the current run of Doctor Who has a spookier, even scarier episode in it, then spare undergarments may be required.
